Blocks of various kinds have been known for years. These range from simple building blocks to puzzle blocks and blocks used as teaching devices of various sorts. In order to better determine the status of the prior art a preliminary patentability search of the existing U.S. patents was conducted in the U.S. Patent Office. It was the intent of the search to develop those U.S. patents which appeared to come closest to the present invention. The search did indeed develop a number of patents relating to various kinds of blocks and the like but no assertion is made that these patents do in fact represent the closest of such art in spite of the fact that that was the intent of the search. The U.S. Pat. Nos. developed by the search are as follows:
CALKINS, 181,637;
DAVIS, 209,385;
BENNETT, 722,668;
BRAINE, 847,545;
CRITCHETT, 884,902;
RHODES, 1,453,728;
PHILLIPS, 1,869,864;
MARTIN, 3,464,145;
ODLER, 3,608,906;
ZEISCHEGG, 3,659,360;
ESTVAN, 3,759,526;
SECTER, 3,773,329 and
MARC, 4,153,254.
With respect to the foregoing patents, CALKINS illustrates a group of puzzle blocks of various shapes to form certain geometrical designs. DAVIS illustrates a device for teaching mathematical relationships such as square and cube roots; in particular, this latter device uses a large block graduated along the upper edges and provided with a cubical recess at one corner for the purpose of placing therein a corresponding number of smaller cubic blocks that fill up the space cutout. CRITCHETT illustrates a series of puzzle blocks of different sizes utilizing staircase-shaped pieces. MARTIN describes a set of blocks such that one face of each block is used in creating an over-all design formed by all the blocks of the set. ESTVAN discloses game pieces with patterns formed by joining pairs thereof. MARC (and others) describes a three-dimensional puzzle game, this one utilizing polyhedrons of different volumes to form an overall cubical or parallelepiped-like block.